An Air New Zealand flight to Christchurch has been delayed after a person tried to bring a rifle on board.

A passenger on the plane said the pilot announced that passengers tried to bring a rifle on to the plane, but failed to follow correct check-in procedure.

The flight was due to depart at 2pm.

The passengers who attempted to bring the rifle on board had been off-loaded, along with their luggage.

They were escorted off the plane by security and engineering staff.

The pilot said "given the situation in Christchurch we are obviously taking no chances".

The passenger said the doors had just been closed and the passengers who tried to bring the gun on board had not returned to the plane.

The pilot's announcement was met with audible shock and disapproval by other passengers.

One woman was heard to say, "Seriously? That is just unbelievable".

The plane is now taxiing to the runway for departure. The security scare delayed take-off by 40 minutes.